Small Business Security Basics: Functions of a Firewall
written by: Ashwin Satyanarayana•edited by: Ronda Bowen•updated: 7/4/2011
Unlike in buildings, where you sometimes have a firewall built to sustain fire and contain it within one area, Network Security firewalls have more threats to handle than just fire (although this could be fire in a way). What are the firewalls supposed to be doing really? Read on to know more
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The firewall is like this brave, faithful soldier who just does what is asked of him. A firewall dissects each one of those packets of Information going out or coming into the network and do just as it is told to do -- all based on the rules that have been defined.
On a very basic level, the firewall sits where the computer network connects with the Internet, although in larger companies, they might want to install a firewall in various locations within their internal networks for added layers of security.
So what does a firewall really do?
Blocking Incoming Traffic depending on Source: As understood from the subtitle, the firewall either restricts or allows the incoming traffic based on the rules available for the firewall, as specified by the organization or Individual. For example, if it is against the company’s Security policy to use Instant Messengers while working, all incoming traffic from any of the popular Internet Messaging platforms will be blocked. Similarly, this system blocks some types of emails from coming into the system
Blocking based on website Content: The firewall doesn’t work just base don source or destination, but it can also filter traffic based on content. For most companies, viewing or surfing websites with adult or pornographic content is strictly forbidden. So all of this content can be effectively blocked by the firewall.
Allocates Internal Resources Even though a firewall is really used for blocking external traffic, it can be used to allocate and spread resources within the company. For instance, junior executives in a company might not have access to the Internet while the seniors do.
Blocking Selected Outgoing Traffic: A firewall not only dissects and prevents trouble incoming traffic, but also does vigilance on outgoing traffic. For example, it prevents access to inappropriate sites by your employees.
Make reports on all network traffic, network activity and such like: A firewall also provides on-demand or frequent reports for the owners or the IT administrators to have a holistic view on what’s happening on the network, a report on all the traffic that went in or out of the computer network.